Just spent another couple of hours trying all kinds of different settings, even deleting the rtorrentvpn image and downloading the latest version. It seems like everything is working again, though I don't know exactly why.. I think that when I set up a bonded dual gigabit connection on my NAS, I set up a different "default gateway" on the NAS as 192.168.1.1 which functions separately from my router? I had to use 192.168.1.0/24 instead of my router's default gateway that I had set up before.. probably
It seems that fixed the "Cannot open TUN/TAP dev /dev/net/tun: No such device (errno=19)" by using this combination of things early in the run command.
--cap-add=NET_ADMIN \
--device=/dev/net/tun \
I think that deleting files/folders within the /config folder also helped fix things.. though I am not sure what or why. The most useful thing that I figured out is that I can move, modify, or delete all of the config folders except for the "openvpn" one and the "rtorrent" to help troubleshoot things, and as long as I don't delete the rtorrent one, I won't lose my rtorrent session and have to recheck all of my files again.
I will post my supervisord.log (minus my PIA login info) if I run into any other issues. I plan to not mess with NAS network settings, drives, SSD cache, etc anymore now that everything is working to my liking.
Sorry that I am so ignorant. Maybe another newbie like me will find my posts useful.